This invention is directed towards coated substrates and in particular toward coated metal substrates that form the exterior of automobiles and trucks.
Acrylic enamel, acrylic lacquer and alkyd enamel finishes are widely used on the exterior of automobiles and trucks. It has been found that an excellent appearance along with depth of color and metallic glamour can be obtained by applying a clear or transparent coat over the conventional colored or pigmented coat. However, the weatherability and durability of these clear coats have been found to be poor since checking, cracking and flaking of the clear coat occurs after relatively short periods of exposure to outdoor weathering which gives the automobile or truck an unsightly appearance. Refinishing of these weathered clear coats is difficult and expensive since the clear coat must be sanded to remove cracked and flaked clear coat before a refinish coat can be applied.
In an effort to retard or substantially reduce checking, cracking and flaking of the clear coat, conventional ultraviolet light stabilizers with and without antioxidants have been added to the clear coat. Also, a combination of a transparent pigment and an ultraviolet light screener have been added to the clear coat as suggested by LaBerge U.S. Pat. No. 3,407,156 issued Oct. 22, 1968. In each of the above cases, the durability and weatherability of the clear coat was increased only a relatively small length of time but not to the extent required for a practical automotive or truck finish.
There is need for a clear coat/color coat finish for metal substrates that will withstand long periods of weathering without failure of the finish. This invention provides a clear coat/color coat finish that has excellent weatherability and durability as required for automobiles and trucks.